When Once Upon a Time returns this fall, the show will look completely different -- but the creative team behind it doesn’t want fans to worry.

Creators Adam Horowitz and Eddy Kitsis addressed the big cast shakeup for season seven -- which sees the departures of main stars Jennifer Morrison, Ginnifer Goodwin, Josh Dallas and others -- at D23 on Saturday in Anaheim, California, downplaying the ramifications of the key exits.

“There was a long-term plan of this story we were telling over the last six seasons and it felt like it was time to close the chapter and start a new one,” executive producer Adam Horowitz said right off the bat. Added executive producer Eddy Kitsis: “It felt like it was time for certain characters to get their happy ending and create a way to keep moving forward with something new.”

Horowitz and Kitsis confirmed that Morrison would return for one episode to wrap up her storyline as Emma in the new season, and all but confirmed that other former regulars would also make returns. “I would be disappointed if we didn’t. That means yes,” Kitsis said, when asked about old Storybrooke favorites popping back in.

“Those six year were all about building those stories to the conclusion we were trying to get to,” Horowitz said. “But they weren’t so much happy endings as happy beginnings. We really want to make sure we honor what happened over those six years, what those characters went through and where they ended up.”

“We’re not interested in erasing those six years or making people feel like they wasted six years for rooting for them,” Kitsis added.

“As much as there is new stuff and some [new] characters, what came before matters and is still is a huge part of what the show is. It’s a new chapter going in a new direction. It’s not a complete reset or a complete reboot, it’s a new chapter,” Horowitz explained.

The season six finale cliffhanger -- where adult Henry (Andrew J. West) meets his daughter Lucy (Alison Fernandez) at his door -- left many fans scratching their heads and wondering where the show was going. Horowitz and Kitsis revealed that the premiere opens in Seattle -- and with a familiar face. “We’re going to pick up with Jared [Gilmore]’s Henry and we’re going to find him as he leaves home,” Kitsis revealed, referencing the younger Henry viewers have known the past six years.

Though the modern-day action will take the story away from Storybrooke (there’s a good chance we’ll see that place “a few times” throughout the season), adult Henry will find himself in a new Enchanted Forest where he’ll meet his wife and mother of his daughter. Devious Maids star Dania Ramirez, who was cast earlier this month, was revealed to be playing a different kind of Cinderella and Henry’s wife(!).

Colin O’Donoghue, who plays fan favorite Captain Hook, joined the panel midway through, and it doesn’t sound like his character will be in a good emotional place when the new season kicks off.

“We meet Colin in new circumstances in the premiere and in the second episode, we really delve into what happened to him,” Horowitz coyly teased, alluding to Emma’s absence and Hook’s presence in Seattle. Episode two will include flashbacks filling in the blanks of what led up to his current situation. “It will explain where he is, what he is, what happened.”

Could Hook’s new reality cause him to revert back to his old ways? “There’s always a danger for Hook to return to his villainous ways but I think his good heart [stops] him from going all the way,” Kitsis assured, adding that #CaptainSwan fans needn’t worry about Hook potentially moving on from “soulmate” Emma. “How can he look elsewhere?”

Another question that will be answered early will be whether Hook and Emma have a kid together. “[We’ll] answer that at the beginning of the season,” Kitsis confirmed.

On a lighter note, O’Donoghue charmed the D23 crowd, sharing a harrowing story of him breaking his foot during filming of the musical wedding episode in season six (FYI: it’s still broken) and serenading the audience with a song.